At present, a short-range optical amplification modules has already been disclosed. In order to meet the imaging quality requirement, the module usually comprises a plurality of optical devices. As shown in FIG. 1, it includes, sequentially from the image side to the object side, a reflective polarizing plate 01, a first phase delay plate 02, a lens unit 03 and a second phase delay plate 04. In the lens unit 03, the optical surface adjacent to the second phase delay plate 04 is a transflective optical surface. In use, the optical image from the object side is transmissively amplified by the lens unit 03, then reflected by the reflective polarizing plate 01, and again amplified by the lens unit 03, and finally enters the human eye via the reflective polarizing plate 01. In the optical amplification module, the lens unit is the core part that influences the amplification effect on the optical image.
Since each optical device takes a certain amount of installation space, the size and volume of an optical amplification module consisting of a plurality of optical devices are usually both very large, which especially cannot meet the compact and ultrathin structure requirement for an intelligent Virtual Reality (VR). Therefore, a short-range optical module that has high amplification factor in a small space needs to be designed for application in VR devices. Moreover, VR devices focus on providing better user experience, which requires that a VR device should achieve a wide field angle, a large eyebox and high-quality imaging effect, etc. Such technical objects are directly related to the optical features of the above lens assembly.
Therefore, in order to attain the above objects, parameters need to be set for the lens assembly in a short-range optical amplification module, so that the above objects can be realized within the whole range of use of the VR device.